The present disclosure relates to a sheet housing device housing an ejected sheet and an image forming apparatus including this sheet housing device.
An image forming apparatus may include a post-processing device carrying out post-processes, such as punching or stapling, with respect to a sheet on which an image has been formed. The post-processing device functions as a sheet housing device stacking and housing a post-processed sheet. The sheet housing device includes a stacking tray stacking the post-processed sheet and may include an elevating mechanism to elevate the stacking tray in accordance with the sheet stacking quantity. The elevating mechanism is configured, for example, so that a timing belt is windingly stretched between a driving pulley, such as a winding pulley, and a driven pulley, the stacking tray is fixed to a part of the timing belt and the timing belt is rotated to elevate the stacking tray. In a driving mechanism for such a timing belt, there is a possibility that belt coming-off (dropping-off) or belt tooth skipping of the timing belt occurs.
For example, an image forming apparatus may include a timing belt driving device in which a tooth skipping preventing member is disposed to face to a timing pulley subjected to tooth skipping preventing. The tooth skipping preventing member is provided at a position at which a separation distance from an outside surface of the timing belt wound around the timing pulley is smaller than a height of meshing between the timing pulley and the timing belt.
However, in the timing belt driving device as mentioned above, because the separation distance between the belt tooth skipping preventing member and the outside surface of the timing belt needs to set smaller than the height of meshing between the timing pulley and the timing belt, a positional relationship of the belt tooth skipping preventing member with respect to the timing pulley is severe. In the sheet housing device (the post-processing device) of the image forming apparatus, because the timing belt elevating the stacking tray often has the height of the teeth set low as 1.9 mm, 1.1 mm or 1 mm or less, it is very difficult to precisely dispose such a belt tooth skipping preventing member.